The primary objective of this proposal is to identify the genetic mutation(s) responsible for Setleis Syndrome (SS). SS is a form of ectodermal dysplasia believed to be inherited as an automosal recessive trait. It is characterized by bilateral temporal marks, an aged leonine appearance, puckered skin about the eyes, absent eyelashes on both lids or multiple rows on the upper lids and none on the lower lids, a mouth and chin that feels rubbery, and eyebrows that slant sharply upward. The gene responsible for SS has not been identified and the molecular basis for SS is not known. DNA analysis of Puerto Rican Setleis patients failed to establish linkage with candidate gene regions 1q32-44, 2q11-13, 3q27, 11q23-q24 and 13q12 and 1p36. We propose to: 1) make a genome-wide scan to identify the Setleis gene locus, 2) do gene mapping in order to refine the genetic candidate region for the SS gene, 3) engage in molecular studies to resolve the physical and genetic map of the gene and evaluate the genes and 4) identify the specific mutation responsible for Setleis Syndrome in these patients. The identification of the SS gene could lead to tool s for the diagnosis and treatment of this condition and other ectodermal dysplasias.